An adhesive film is available in various fields requiring adhesion. Especially, the adhesive film can be used to protect an element or device that is susceptible to external factors, such as moisture or oxygen.
As illustrated in FIG. 1, an adhesive film is prepared to have a structure having an adhesive layer 3 in an uncured state, at least one protective film 1 or 2 for preventing adhesion of foreign substances to the adhesive layer, and the like. In addition, the adhesive film used for protecting an element or device that is susceptible to external factors, such as moisture or oxygen, mostly includes a moisture absorbent, and the like.
However, in general, an adhesive film is not subjected to the following process directly after being produced. In a general case, the adhesive film is distributed, or stored before being used in an adhesion process. Therefore, as illustrated in FIG. 1, in the case of exposing side faces of an adhesive layer to external air, a moisture absorbent included in the adhesive layer loses its function due to moisture in the air during a distribution and/or storage process of the adhesive film. Therefore, a problem in which such an adhesive film cannot properly play a role in encapsulating an element or device may be present.
In addition, at the time of encapsulating an element or device with an adhesive film, the adhesive film is disposed between an upper panel and a lower panel and then thermo-compressed. In this case, a defect in which part of an adhesive layer in an uncured state leaks out of the adhesive film, thereby not forming an adhesive layer having a uniform thickness, may occur.